ios - 将代码中的文本分配给 UILabel! swift 2.2

Question

使用 iOS 8/Swift 1 中的教程创建示例应用程序，尝试使用 Xcode 7.3/Swift 2.2 将文本分配给标签。提前致谢。

import UIKit

class ViewController: UIViewController {

    @IBOutlet var ageCat: UITextField!

    @IBOutlet var resultAge: UILabel!

    @IBAction func findAgeButton(sender: AnyObject) {

        var enteredAge = Int(ageCat.text!)

        var catYears = enteredAge! * 7

        resultAge = "Your cat is \(catYears) in cat years"

    }
}

Answer 1

将您的 IBAction func findAgeButton 替换为以下内容:

@IBAction func findAgeButton(sender: AnyObject) {

// Here the variable is unwrapped. This means the code after it is not executed unless the program is sure that it contains a value.
if let text =  ageCat.text {
    // You can use the unwrapped variable now and won't have to place an exclamation mark behind it to force unwrap it. 
    let enteredAge = Int(text)
     if let age  = enteredAge {
      let catYears = age * 7
      resultAge.text = "Your cat is \(catYears) in cat years"
   }
  }
}